1. Field of the Invention
The present invention relates to an apparatus that corrects a white line of an ink jet printer and a method of controlling the apparatus, and in particular, to an apparatus that corrects a white line of an ink-jet printer. The apparatus is capable of preventing a white line from being produced by using dummy nozzles when overfeeding of a recording paper causes a release of tension of the paper in a mechanical mechanism, in which a pickup roller loads the recording paper and a feed roller feeds the paper. The release of tension of the paper arises when the tail end of the paper passes out of the pickup roller. The present invention further relates to a method for controlling the apparatus.
2. Description of the Related Art
An ink-jet printer is formed with a plurality of nozzles in a head of a cartridge of a printing device. Such an ink-jet printer typically has a resolution of about 300 to 1200 DPI (Dot Per Inch) and implements mono printing or color printing depending on the type of the cartridge.
The operation process of such an ink-jet printer is described in detail with reference to FIG. 1. A paper P is loaded in a paper-loading section 10 and a pickup roller 21 picks up and feeds it to a paper transfer path, on which the transfer to print is performed.
If the paper picked up by the pickup roller 21 in this manner is detected by a paper-detection sensor 40, the paper P is fed by the compressive force between a feed roller 22 and a friction roller 23 which are rotating and consequently the paper P is transferred to a printing position in which an ink cartridge 30 is located.
If the paper is transferred to the printing position, a cartridge driving motor is driven and a belt, which is driven in cooperation with the cartridge driving motor, is driven left and right, as a result of which the cartridge mechanism slides left and right and the printing is implemented on the transferred paper P through a plurality of nozzles 31′ (FIG. 3) formed in the head 31 of the cartridge 30.
Then, the paper P is gradually moved on a base frame 50 while the paper is being printed line by line by the nozzle 31′, formed in the head 31 of the cartridge 30, and the printed paper P is discharged by a paper-discharging roller 24 when the printed paper P arrives at a paper-discharging port.
In this case, the paper P, picked up in the paper loading section 10, is transferred to the printing position and fed according to a preset feeding amount to print by the rotation of the feed roller 22 and the friction roller 23. However, there is a problem in that when the tail end of the paper passes out of the pickup roller 21, while the paper is being fed in a preset feeding amount, release of tension of the paper is caused, and due to the release of tension, the vertical component of feeding force exerted by the pickup roller 21 is lost, as a result of which the paper is overfed so as to exceed the preset feeding amount, and a white line is produced in the final printed paper.
Detailed description is made with reference to FIG. 4. At the moment the tail end of the paper passes out of the pickup roller 21, the feed roller 22 and the friction roller 23 feeds the paper in the preset feeding amount and the vertical component of feeding force which has been exerted by the pickup roller 21 and has held the paper is lost, as a result of which the paper is overfed to the extent of α. That is, in the overfeeding position, the paper is overfed to the extent of the sum of the preset feeding amount a and an overfed amount α, i.e., to the extent of a+α. Because the nozzles 31′ are controlled so that the printing is implemented in a preset printing width in the state that the paper has been overfed to the extent of a+α, the overfed amount α remains without being printed. Therefore, there is a problem in that a white line is produced on the printed paper to the extent of 60 and thus deteriorates the quality printed image.